1. Field of the Invention
The present invention relates to a method for fabricating a pixel structure, and more particularly to a method for fabricating a pixel structure using a relatively fewer number of masks.
2. Description of Related Art
With the progress of modern visual communication technology, various types of displays have been widely adopted in display screens of consumers' electronic products such as cell phones, notebook computers, digital cameras, and personal digital assistants (PDAs). Among these displays, the liquid crystal display (LCD) and the organic electroluminescence display (OELD) have become the mainstream on the market due to their advantages of lightness, compactness, and lower power-consumption. The manufacturing processes for both the LCD and the OELD include forming a pixel structure arranged in array on a substrate through a semiconductor manufacturing process.
FIGS. 1A through 1G are cross-sectional views depicting a process of fabricating a conventional pixel structure. First, referring to FIG. 1A, a gate 20 is formed on a substrate 10. Next, referring to FIG. 1B, a first dielectric layer 30 is formed on the substrate 10 to cover the gate 20. Thereafter, referring to FIG. 1C, a channel layer 40 is formed on the first dielectric layer 30. Afterwards, referring to FIG. 1D, a source 50 and a drain 60 are formed over the channel layer 40. After that, with reference to FIG. 1E, a second dielectric layer 70 is formed over the substrate 10 to cover the channel layer 40, the source 50 and the drain 60. Next, referring to FIG. 1F, a contact hole H is constructed on the second dielectric layer 70. Afterwards, as shown in FIG. 1G, a pixel electrode 80 is formed on the second dielectric layer 70. A part of the pixel electrode 80 is filled in the contact hole H and is electrically connected to the drain 60. As such, the fabrication of the pixel structure 90 is completed.
To sum up, the fabrication process of the conventional pixel structure 90 is mainly carried out by forming the gate 20 with use of a first mask, forming the channel layer 40 with use of a second mask, forming the source 50 and the drain 60 with use of a third mask, forming the contact hole H with use of a fourth mask, and forming the pixel electrode 80 with use of a fifth mask. Accordingly, the conventional five-mask process of fabricating the pixel structure 90 is rather complicated and time-consuming, which leads to higher possibilities of defects and lower yield of the pixel structure 90. In addition, with the complicated manufacturing process and long time lapse of fabricating the conventional pixel structure 90, the manufacturing costs arisen from the fixed costs of the machines and equipment or the material costs are then increased.